Long ago I discovered that q: opens a
[Command Line] buffer where I can enter and edit an ex command line using all the power of Vim.
Next, some time ago, I discovered that I can access that mode even while in the middle of editing a command line by pressing Ctrl+f.
For all the above I've found the doc.
But today, I've discovered that hitting Ctrl + C while in that window, the line being edited is copied on the ex prompt which becomes active. It's a bit like it's the inverse of Ctrl+f.
However, I couldn't find the documentation for it. Can you enlighten me?